JPS634248Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic recording and reproducing device, in which an operation command signal input terminal provided in an audio signal processing circuit that is selectively set to recording or reproducing mode is connected to The purpose of this invention is to force the circuit to enter the recording mode by transmitting the signal for the recording mode that has priority over it, thereby simplifying the circuit configuration.

Magnetic recording and reproducing devices are equipped with a so-called post-recording mode to improve their functionality. It is a method that records information on other channels while reproducing information on one channel. For example,
In a VTR, this is used to record audio information suitable for the picture information while playing back recorded information.
Furthermore, when two audio channels are provided, this is used when one is being played back while recording is being performed on the other. Recently, the use of ICs has progressed in devices, and audio signal processing circuits such as recording amplifiers, line amplifiers, noise reduction circuits, and operation mode switching circuits are configured with a single IC. and,
The operating mode of the audio signal processing circuit is set to the recording mode during recording or dubbing, and to the playback mode during playback, based on a recording, playback, or post-recording mode signal given from the system controller. By the way, in the conventional example, this mode setting is performed depending on the presence or absence of a playback mode signal to the mode command signal input terminal of the circuit, so the circuit is set to the recording mode while receiving the playback mode signal from the system controller. If you want to set it to , you must use an after-recording mode signal to cut off the transmission of the playback mode signal to the input terminal.

In order to simplify the configuration by omitting the switching circuit that performs this cutoff, the present invention transmits a playback mode signal to the operation command signal input terminal of the audio signal processing circuit during the post-recording mode, and also sets a recording mode that takes precedence over it. signal to force the circuit into recording mode.

Next, the present invention will be explained according to illustrated embodiments. 1st
The figure is a block diagram of the configuration of this device, and FIG. 2 is an explanatory diagram of the operation. In Fig. 1, 1 and 2 are audio signal input terminals for the first and second channels;
is an audio signal processing circuit for each channel, 5 and 6 are magnetic heads for each channel, 7 and 8 are audio signal output terminals for each channel, 9 is a system controller, 10 is an oscillation circuit, and 11 and 12 are each channel. bias trap circuits 13 and 14 are first and second switch circuits of the first channel;
16 is the first and second switch circuit of the second channel; 17, 18, and 19 are switching circuits; D ₁
~ _D6 is a current prevention diode, and 20 is an inverter. Since most of the configurations of each channel are the same, the second channel will be described in detail below as a representative.

The audio processing circuit 4 has a first input terminal 41 for inputting an audio information signal for recording, a second input terminal 42 for inputting a reproduced audio information signal, and a first output for outputting an audio information signal to be recorded. Terminal 44 and
It is equipped with a second output terminal 43 for outputting a reproduced audio information signal and a third input terminal 45 for inputting an operation mode command signal, and a recording amplifier 4 inside.
6, a line amplifier 47, a noise reduction circuit 48, an operation mode switching circuit 49, and the like. When the recording mode signal (high level) is input to the third input terminal 45, the first input terminal 41
A transmission line is opened from the second input terminal 42 to the first output terminal 44, and when a reproduction mode signal (low level) is input, a transmission line is opened from the second input terminal 42 to the second output terminal 43. .

Based on instructions from the outside, the system controller 9 connects the first line 91 during playback, the second line 92 during recording, and the third line 9 during post-recording.
3, respectively, to output operation mode command signals as shown in FIG. 2a, b, and c. Here, it should be noted that during post-recording, a high-level signal is transmitted on the third line 93, and a high-level signal is also transmitted on the first line 91, as in the case of reproduction.

The oscillation circuit 10 applies an AC bias to the magnetic head 6 and also applies an erase signal to an erase head (not shown), and the switching circuit 1
An oscillation output is given to both heads by receiving a power supply (12 volts) with 9 outputs. 1st
The switch circuit 15 is of a normally closed type, and unless a high level signal is applied to the control terminal 21, one end 22a of the coil 22 of the magnetic head 6 is connected to the reference potential point (earth) 23. On the other hand, the second switch circuit 16 is of a normally open type, and connects the other end 22b of the coil 22 to the ground 23 only when a high level signal is applied to the control terminal 24. Each switching circuit 17,1
8 and 19 operate so as to apply power (12 volts) to the next stage circuit when a high level signal is received at each input terminal, while not applying this when a low level signal is received. There is. Next, the operation will be explained. First, the playback operation will be explained. When the system controller 9 instructs the device to perform a regeneration operation, the system controller 9 connects the first, second, and third lines 91, 92,
A mode signal shown in area A in FIG. 2 is output to 93. The high level signal on the first line 91 is inverted by the inverter 20, and the second and third lines 92, 9
Since a low level signal is output to the switching circuit 3, a high level signal is not applied to each switching circuit 17, 18, 19. Therefore, the first and second switch circuits 15 and 16 are both set to the normal position (P side), and the operation mode switching circuit 49 of the audio signal processing circuit 4 is also set to the initial position. The reproduced signal is transmitted from the second input terminal 42 of the audio signal processing circuit 4 to the second output terminal 4.
3 and is transmitted to the audio signal output terminal 8. In this reproduction mode, the oscillation circuit 10 does not operate because power is not applied through the switching circuit 19.

Next, the recording mode will be explained. When the recording mode is instructed, the system controller 9 applies a mode signal shown in area C in FIG. 2 to each of the first, second, and third lines 91, 92, and 93. Therefore, each switching circuit 17, 18, 19 operates so as to apply power to its output, and the first and second switch circuits 17, 18 and the operation mode switching circuit 49 operate in the opposite manner to that during reproduction. mode. Therefore, the input signal from the audio signal input terminal 2 is sent to the first input terminal 41 of the audio signal processing circuit 4.
The signal is then transmitted to the first output terminal 44 and applied to the magnetic head 6. At the same time, the oscillator circuit 10 is energized, so that the audio signal is recorded with AC bias on the audio track of the recording medium.

When the dubbing mode is set, the system controller 9 controls the first, second, and third lines 91 and 9.
A mode signal shown in area B in FIG. 2 is applied to 2,93. Therefore, only the switching circuit 19 outputs power, and the other switching circuits 17 and 18 do not output power. Therefore, the first switch circuit 1
5 and the oscillation circuit 10 are operated in the same manner as during recording, but the second switch circuit 16 and the operation mode switching circuit 49 operate in the same manner as in the recording mode. No recording mode signal is received from 18. However, since both circuits 17 and 18 receive high level signals from the third line 93 and the switching circuit 19, both are set to the recording mode. In the first channel, in this post-recording mode, the first and second switch circuits 13, 14 and the operation mode switching circuit 39 are all the same as in the playback mode. Thus, each third input terminal 3 of the audio signal processing circuit 3, 4
5, 45, the first channel is shown in Figure 2 d, the second
The signals shown in FIG. 2e are applied to the channels, and as a result, the operation mode patterns of the first and second channels are as shown in FIG. 2f and g.

As described above, the device of the present invention transmits a recording mode signal that takes priority over the reproduction mode signal even though the reproduction mode signal is being transmitted during the dubbing mode. Since the signal is received from three lines, there is no need to use switching means or the like to cut off the reproduction mode transmission signal, contributing to the simplification of the circuit configuration. In particular, the device according to the present invention has two channels for audio signals, and is useful when one is set in playback mode and the other in recording mode.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of one embodiment of the device of the present invention;
FIG. 2 is an explanatory diagram of the operation of the device. Explanation of main drawing numbers, 3, 4... Audio signal processing circuit, 91, 92, 93... 1st, 2nd, 3rd lines, 9... System controller, 10... Oscillation circuit, 5, 6... ...magnetic head, 15, 16... first and second switch circuits, 17, 18, 19... switching circuit.

Claims (1)

[Scope of utility model registration request] A first input terminal for inputting an audio information signal for recording, and a second input terminal for inputting a reproduced audio information signal.
It has an input terminal, a first output terminal for outputting the audio information signal to be recorded, a second output terminal for outputting the reproduced audio information signal, and a third input terminal for inputting the operation mode command signal. The recording or reproduction mode is selectively set in accordance with the operation mode command signal, and a transmission path is established from the first input terminal to the first output terminal during recording and from the second input terminal to the second output terminal during reproduction. The first and second audio signal processing circuits invert the playback mode signal, which is complementary to the recording mode signal, to create the operation mode command signal and output it to the third input terminal of the first audio signal processing circuit 3. is directly applied to the third input terminal of the second audio signal processing circuit 4 via a backflow prevention diode, and the playback mode signal and the dubbing mode signal are applied when the dubbing mode is set. a system controller 9 that sets the system controller 9 in an active state, and creates a signal that sets the second audio signal processing circuit to a recording mode with priority over the operation mode command signal creation means when the dubbing mode signal is in an active state. and means 19 for applying an electric current to a third input terminal of the second audio signal processing circuit via a backflow prevention diode.